Yes! Outside sports can definitely help. On the USAFA side the fencer twins, two very competitive fencers in my class are an example. Also for me, most of the tennis I played was not high school as my region was fairly weak. I have also had classmates with high level belts in various martial arts or for the case of a small or homeschooled kid, a mainstream sport such as soccer played at the club level instead because it was more competitive or the school didn't have a team.
Rev clubs are probably not great for this since the competition element isn't really there, but every case is different. That's what the essays are for, to explain how you are unique.